In the last decade, there has been a rising interest in the problem of low health literacy in the United States. While there is increasing evidence that low health literacy is associated with worse health outcomes, there have been no studies that have identified the specific mechanisms that link health literacy and health outcomes. There is a need for research to explore the mechanisms through which low health literacy places patients at risk. We hypothesize that one mechanism through which low health literacy impacts health outcomes is adherence rates of chronic medications. The first phase of the planned work will be a retrospective cohort analysis. In a face-to-face interview, we will measure hypertensive patients' health literacy and disease knowledge. Through automated medical record review, we will measure their rates of antihypertensive medication refills; blood pressure control; and health services utilization including clinic visits, emergency department visits, and hospitalizations in the preceding year. Comparisons will be made between patients of low health literacy and those with adequate health literacy. The second phase will utilize focus groups of those patients with low literacy and low medication adherence to explore the links between health literacy, disease knowledge and medication adherence. With better understanding of the mechanisms linking health literacy and health outcomes, the next step will be to design and test interventions, at both the patient and health care provider level, in attempt to minimize these disparities in health care outcomes.